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Welcome to Hotrodders, Burnout :thumbup:

A good cam and better flowing exhaust will definitely wake it up some, depending on how it's built now. I assume it's stock?

To get a lot out of a 305 you either have to throw alot of money at it (metaphoricly :D ) or do something clever, like a stroker build on it.
 

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chevy 305,can it be fast ?

There was a very interesting article in the latest issue of Engine Masters,they took an older stock 305,put on a set of heads,a cam,intake and new carb and got 372 HP.I forget what heads they used,but the numbers were certainly impressive.They didnt touch the bottom end.
 

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Don't know about "fast" but they can be made to run pretty good, they do seem to like cams with a little tighter LSA than a 350. What exactly are your goals? I know a 305 HO with a 200-4R and a set of 3.73 gears in a G-body is pretty responsive, maybe not what most people consider "fast" but it will make people turn around and look when you stab the go pedal and makes stop light to stoplight driving more fun. It would definitely put your driving priviledges in peril. ;)
 

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Discussion Starter · #8 ·
F-BIRD'88 said:
What are you willing to do to get more power?
A 305 responds to moda just like any other SBC.

Your 305 is a low perf base engine. with low compression small heads and valves and tiny tiny camshaft and real bad exhaust manifolds. All this needs to be changed.

A hot rodded 305 will need a high(er) stall converter and a higher rear gear ratio than a simular hopped up 350.
The torque bnd gets shifted much higher in a 305 or any small ci motor when modded.

EG: the Monte Carlo SS 305 motor came with a special 3000 stall lockup converter and 3.73's.

To start with pull off one valve cover and get the cylinder head csting number off your heads.
Yes you can make your 305 fast. How fast do you want to go? 14's 13's 12's..... Do you want a radical street machine, or is gas mileage a concern. What do you use the car for, most? Will take work on your part thou.
Well i want to run about 13's and its my only car so i have to get desent gas mileage.Thanks people for the information i now have an idea of what i got to do.I was thinking about changing the carb,manifold,heads,cam,and putting 3.73's gears on it.What do yall think?
 

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I had an 86 GMC Cabballero (same as ElCamino) that ran 13.80s with a very mild 305 with 3.23 gears.
I used KB143 +.030 pistons, with the L-98 Corvette aluminum heads gave me just shy of 10.0:1 compression. I used a Comp cams Extreme energy gring, I forget whitch one, one of the milder ones, I think it was a XE262. it wass all in by 6000 RPMs. I ran a Performer intake, 570 Holley, DUI ignition,Dynomax headers, 2.5" dual exhaust through a pair of catco convertors & Dynomax Turbo mufflers. It was mild enough that it would pull 16" of vacuum at idle, pass IM240 smog. It got horrible MPG however, but it wasnt a daily driver, I wasnt to consened about the MPG. I used a T-350 tranny with a 2200 RPM convertor.
It was very timing sensitive & also even the smallest change in fuel mixture would make big changes for better or worse. John
 

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I basically have a canned respose to this question, as it has been asked several times (try a search you'll probaly find some good threads). ANyway, here it is:

If your goal is overal performance, or to just have a quicker car, start from the back forward. First thing maybe gears, then an overdrive trans (which generally have a lower first gear and allow you to run a steeper rear gear more comfortably). Torque converter is a great addition as well. I would choose parts that you think will work well with a larger cube motor later on. That way if you put one in you're good to go. And if you never get to it, you can just run it as is.

You could probably find an entire rear end with posi and just slide it in there for 2-500 bucks (I'm not sure what they're going for for your model/year). Stall converters are anywhere from 150-400 dollars (depending on the trans). A trans in decent shape might run you 200-600 depending on how many they have on hand etc. 1000 dollars will get you going a lot faster if you spend it with the above method than if you throw it at a 305. The heads you'd need to make power are going to cost 6-800 bucks alone, and with no other swap (cam etc) you'd gain maybe 35 horse even with really nice heads.

K
 

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killerformula said:
I basically have a canned respose to this question, as it has been asked several times (try a search you'll probaly find some good threads). ANyway, here it is:

If your goal is overal performance, or to just have a quicker car, start from the back forward. First thing maybe gears, then an overdrive trans (which generally have a lower first gear and allow you to run a steeper rear gear more comfortably). Torque converter is a great addition as well. I would choose parts that you think will work well with a larger cube motor later on. That way if you put one in you're good to go. And if you never get to it, you can just run it as is.

You could probably find an entire rear end with posi and just slide it in there for 2-500 bucks (I'm not sure what they're going for for your model/year). Stall converters are anywhere from 150-400 dollars (depending on the trans). A trans in decent shape might run you 200-600 depending on how many they have on hand etc. 1000 dollars will get you going a lot faster if you spend it with the above method than if you throw it at a 305. The heads you'd need to make power are going to cost 6-800 bucks alone, and with no other swap (cam etc) you'd gain maybe 35 horse even with really nice heads.

K
Read it, learn it, live it! Excellent advice.:thumbup:
 

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I agree with killerformula. Beyond that, when you start buying parts for the motor, I recommend buying parts that you can use on a 350 or 400 based motor in the future. I would use headers/intake/cam (especially if it is a roller) that would also work in a larger motor in the future. I would not recommend buying a set of aftermarket 305 heads or getting any head work done on yours (unless you do it yourself) except for springs. If you ever go to another motor, they may will not work due to the small chambers, and the aftermarket options open up greatly when you get away from 305 heads.

Adam
 

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Discussion Starter · #14 ·
F-BIRD'88 said:
I think its very do--able. What transmission do you have now? Whats your budget and skill level? what performacne parts do you have laying around that you can either use or trade for better ones? Again what head castings are on the motor now? Does it have to pass an emissions test? Visual inspection?
I think it has a 200 trans.I want to get the most horsepower i can with about $1500.I dont have any parts laying around,this is my first project car so im a beginner,but i do have some experiance working on cars,just the basics.Im not sure what head castings are on the car right now,and it just has to pass a visual inspection.
 

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Like Killer said, start at the back, find out what gears you have, probably 3.08s, swap em for 3.23 or 3.42s , change trannys to a 700R4, thats been built put a converter in it. If you still have any money left, put on some small tube headers & free flowing exhaust.
 

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Discussion Starter · #16 ·
stepside454 said:
Like Killer said, start at the back, find out what gears you have, probably 3.08s, swap em for 3.23 or 3.42s , change trannys to a 700R4, thats been built put a converter in it. If you still have any money left, put on some small tube headers & free flowing exhaust.
Thanks for the help,i would of never thought to start at the back and work my way to the front.I think it has 2.73 gears,they got to go huh?Well thanks.
 

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I spent a lot of time working on the old 305 that was in my bird before I put the stroker in. I took off the stocker heads and put on H.O. camaro heads from the late-80's which are actually decent (1.84's if I remember right, which is just right for a mild 305). I ordered a cam from summit and put that in it. It was a 224/234 if I remember correctly, which they stated was the largest size for a stock converter. It had a 2.73 posi in the back, btw. I also put a duel plane edelbrock intake on it as well as a 4 barrel 600cfm carb. Put headers on it, full duels all the way back.

The car was pretty much a dog. It would pull pretty good above 2500 RPM but you spent all day riding around in 1st gear to do it. I could have spent 1/10th the amount of time and probably 1/2 the money and just put the gears in it that I ended up just putting in it later anyway.

You spend a grand on the motor and I'll spend a grand on gears and a converter, guaranteed I'll blow your doors off.

K
 

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Discussion Starter · #18 ·
killerformula said:
I spent a lot of time working on the old 305 that was in my bird before I put the stroker in. I took off the stocker heads and put on H.O. camaro heads from the late-80's which are actually decent (1.84's if I remember right, which is just right for a mild 305). I ordered a cam from summit and put that in it. It was a 224/234 if I remember correctly, which they stated was the largest size for a stock converter. It had a 2.73 posi in the back, btw. I also put a duel plane edelbrock intake on it as well as a 4 barrel 600cfm carb. Put headers on it, full duels all the way back.

The car was pretty much a dog. It would pull pretty good above 2500 RPM but you spent all day riding around in 1st gear to do it. I could have spent 1/10th the amount of time and probably 1/2 the money and just put the gears in it that I ended up just putting in it later anyway.

You spend a grand on the motor and I'll spend a grand on gears and a converter, guaranteed I'll blow your doors off.

K
Orite sounds good,I was thinking of 3.42s.What do you think?
 

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3.42's are great. 3.73's are very streetable, but only with an overdrive. Trust me, I have them with a Th350 and it drives you NUTS on the highway. My recommendation is to do the 3.73's only if you have serious plans to do an overdrive in the not-so-distant future. Remember, overdrive transmissions usually have steeper first gears (especially the 700-R-4 at 3.06) so you may not even need to go as steep on the gears.

K
 

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F-BIRD'88 said:
This is the thing... a 224-234 summit cam in a 305 needs a good bit of compression ratio (stock 8.5 will suck) and a 3000-3500 stall converter and at least a 3.73(with a short tire) 4.10 better. the cam, converter and rear gear ratio has to match or... "its a dog till i get going"
With this cam the whole torque band (rpm range) gets shifted up at the expence of low end torque.
Also needs cylinder head flow improvement. Either port the stock heads or replace them with better ones.

Actually the cam is rated by summit, as I said before, to run with a stock stall converter and with 8.5:1 compression.

The grinds on these cams are old, that's why they're cheap. They're not comparable to a 224/234 comps cam. The ramp speeds on these older cams are slower, so its spends less time in the high lift range. You can't judge a cam just by its @.050 numbers, at least in this case.

K
 
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